P2.16-27 Longitudinal Skeletal Muscle Changes in Patients with Advanced Squamous Cell Lung Cancer

Abstract

Cancer cachexia is a multifactorial syndrome characterized by an ongoing loss of skeletal muscle mass. Skeletal muscle depletion is prevalent in lung cancer patients and is associated with poor prognosis. This study analyzed the changes in skeletal muscle mass until the end of life in patients with advanced squamous cell lung cancer (SQCLC). This retrospective study consisted of 70 consecutive patients who underwent palliative chemotherapy for SQCLC and died between September 2010 and March 2015. A cross-sectional area of muscle at the level of the first lumbar vertebra (L1) was measured using computed tomography scans. An artificial intelligence algorithm was developed and used for serial assessment of muscle area. Sarcopenia was defined as a L1 skeletal muscle index of ≤46 cm2/m2 for men and ≤29 cm2/m2 for women. Median interval between last scans and deaths was 1.3 months (95% CI, 0.9 to 1.7). The median age was 69 years and 82% of patients were male. Sarcopenia was present in 58 patients (76%) at baseline. Median overall survival was 8.7 months (95% CI, 5.9 to 11.5). All patients experienced net muscle loss over the disease trajectory. Mean percentage loss of skeletal muscle between the first and last scans were 16.5±11.0%; mean decrease of muscle area was 17.28±13.00 cm2 (p <0.001) at a rate of 2.64±2.36 cm2/month. Skeletal muscle loss was accelerated over time. Patients lost an average of 1.64±1.02 cm2, 2.00±1.52 cm2, 2.91±2.69 cm2, and 4.82±4.59 cm2 skeletal muscle per month during the last 12, 9, 6, and 3 months, respectively (p <0.001). Patients losing skeletal muscle at ≥ 3.24 cm2/month (upper tertile) had shorter overall survival compared with patients who lost muscle at slower rate (median, 5.7 vs. 12.0 months; p <0.001). Patients with advanced SQCLC lose significant amount of skeletal muscle until death. The rate of muscle mass reduction is faster at the end of life. Patients who lose muscle at the higher rate have shorter survival time.